rs397507762

Positions:

• chr13-32326283-G-A
• chr13-32326283-G-C
• chr13-32326283-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000059.4(BRCA2):​c.516+1G>A variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: BRCA2 NM_000059.4 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 6.49

Genes affected

BRCA2 (HGNC:1101): (BRCA2 DNA repair associated) Inherited mutations in BRCA1 and this gene, BRCA2, confer increased lifetime risk of developing breast or ovarian cancer. Both BRCA1 and BRCA2 are involved in maintenance of genome stability, specifically the homologous recombination pathway for double-strand DNA repair. The largest exon in both genes is exon 11, which harbors the most important and frequent mutations in breast cancer patients. The BRCA2 gene was found on chromosome 13q12.3 in human. The BRCA2 protein contains several copies of a 70 aa motif called the BRC motif, and these motifs mediate binding to the RAD51 recombinase which functions in DNA repair. BRCA2 is considered a tumor suppressor gene, as tumors with BRCA2 mutations generally exhibit loss of heterozygosity (LOH) of the wild-type allele. [provided by RefSeq, May 2020]

BRCA2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.0038997757 fraction of the gene. Cryptic splice site detected, with MaxEntScore 7.6, offset of -39, new splice context is: gtgGTatgt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 13-32326283-G-A is Pathogenic according to our data. Variant chr13-32326283-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 51786.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr13-32326283-G-A is described in Lovd as [Pathogenic]. Variant chr13-32326283-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
BRCA2	NM_000059.4	c.516+1G>A		splice_donor_variant, intron_variant		ENST00000380152.8	NP_000050.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
BRCA2	ENST00000380152.8	c.516+1G>A		splice_donor_variant, intron_variant		5	NM_000059.4	ENSP00000369497.3
BRCA2	ENST00000530893.7	c.147+1G>A		splice_donor_variant, intron_variant		1		ENSP00000499438.2
BRCA2	ENST00000614259.2	n.516+1G>A		splice_donor_variant, intron_variant		2		ENSP00000506251.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary breast ovarian cancer syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 18, 2021	For these reasons, this variant has been classified as Pathogenic. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in BRCA2 are known to be pathogenic (PMID: 20104584). Experimental studies using patient lymphoblastoid cells have shown that this intronic change leads to multiple alternative transcripts, skipping exons 5, 6, and 5 and 6, resulting in truncated protein products (PMID: 12759930, 18489799). This variant has been reported in the literature in individuals affected with breast cancer (PMID: 12759930, 28664449). ClinVar contains an entry for this variant (Variation ID: 51786). This variant is not present in population databases (ExAC no frequency). This sequence change affects a donor splice site in intron 6 of the BRCA2 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 29, 2016	- -

Breast-ovarian cancer, familial, susceptibility to, 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA), c/o University of Cambridge

Oct 02, 2015

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 09, 2017

This pathogenic variant is denoted BRCA2 c.516+1G>A or IVS6+1G>A and consists of a G>A nucleotide substitution at the +1 position of intron 6 of the BRCA2 gene. Using alternate nomenclature, this variant would be defined as BRCA2 744+1G>A. The variant destroys a canonical splice donor site and is predicted to cause abnormal gene splicing, leading to either an abnormal message that is subject to nonsense-mediated mRNA decay or to an abnormal protein product. This variant has been reported in several breast and/or ovarian cancer patients of Belgian decent and has been shown, via RT-PCR, to result in three out-of-frame transcripts, all resulting in a premature stop codon (Claes 2003, Claes 2004, Machackova 2008). We consider this variant to be pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 01, 2023

The c.516+1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide after coding exon 5 of the BRCA2 gene. This alteration has been previously detected in multiple individuals in six unrelated Belgian families with breast cancer; RNA studies showed that this alteration led to skipping of multiple exons (Claes K et al. Genes Chromosomes Cancer. 2003 Jul;37:314-20; Claes K et al. Br. J. Cancer. 2004 Mar;90(6):1244-51; Machackova E et al. BMC Cancer. 2008 May;8:140). This alteration has also been detected in 1/313 unselected Chinese breast cancer patients (Li G. et al J. Cancer Res. Clin. Oncol. 2017 Oct;143(10):2011-2024). Of note, this alteration is also designated as IVS6+1G>A in published literature. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.42	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	32
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.98		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs397507762; hg19: chr13-32900420;